Why Leaves Change Color?

Scientists don't yet fully understand all of the complicated actions and interactions that produce the
spectacular displays of autumn leaf colors that are a highlight of the fall months. Although not fully
understood, several factors affect when and how leaves change color and the hues they produce. These factors include:

Shortening of day length

Cooling temperatures

organic pigments in the leaf cells

sunlight intensity

moisture

tree genetic traits

site characteristics

latitude

altitude

Why are fall trees more intense some years?

Cool Night Temperatures - An extended period of cool night time temperatures below 45 degrees but above freezing helps to develop
more anthocyanins in the leaves bringing out more intense fall colors in trees.

Sunny Days - Bright sun filled days allow the leaves to trap the sugars from the dwindling chlorophyll creating fantastic fall color.

Calm Days - Stormy and windy days help to release the leaves on the trees. An extended period of calm days help to enhance the viewing time of fall foliage.

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